Speeding On Lincoln St During School Hours

We need to have some police presence on Lincoln St during the morning school commute. There is a wonderful crossing guard at MacArthur school named Helen that every day has to yell at the top of her lungs at speeders to "Slow Down!" as they race up Lincoln towards the school trying to get to 128 as fast as possible. This despite a flashing 20 mph sign that actively reports the drivers speed . I have seen this be typically 30 to 40 and even as high as 45 mph on occasion. (I have taken pictures of it as proof) Can we do something here before tragedy strik